WinRT: Fixed game controller axis mappings SDL/WinRT currently uses a separate XInput backend from SDL/Win32, as WinRT has no support for DirectInput. This change makes SDL/WinRT's XInput code snag some recently-changed bits from the Win32-specific, DirectInput + XInput backend, in order to get the SDL_GameController API working again on WinRT, insofar that axes map to the correct parts. TODO: - test all buttons, making sure WinRT maps buttons the same way that Win32 does - consider making the Win32 and WinRT codebases share more stuff, minus the sort of duplication happening via this change. Maybe simulate, or stub-out, DirectInput calls when on WinRT?